1. Technical Field
The present invention relates to a test apparatus, a circuit module, and a manufacturing method.
2. Related Art
A semiconductor device forming an electronic circuit generates heat when operating. In recent years, increased operating speed and further integration of circuits in semiconductor devices has led to an increase in the amount of heat generated by semiconductor devices. As a result, when a large number of semiconductor devices are mounted on a test substrate, it is necessary to cool the semiconductor devices. For example, in a semiconductor test apparatus, electrical circuit elements such as semiconductor devices mounted on a multi-layered test substrate can be cooled by covering the test substrate with a fluid case and passing a cooling agent through the fluid case, as described in Patent Document 1, for example.
Patent Document 1: Japanese Patent Application Publication No. 2002-280507
FIG. 18 shows a conventional method for cooling a test substrate on which electrical circuit elements, such as semiconductor devices, are mounted. As shown in FIG. 18, a multi-layer test substrate 31 is formed by layering a plurality of insulating boards 32 and 34 including epoxy resin and a pre-preg 33 including glass fiber base material, for example. The surfaces of the test substrate 31 include electrical circuit elements such as semiconductor devices and have a test circuit 36 and a test circuit 37 mounted respectively thereon. The test substrate 31 is connected to another test substrate via a connector 60 and a connector 64.
In order to lessen the temperature increased due to heat generated by the test circuit 36 and the test circuit 37, a sealing section 38 and a sealing section 39 functioning as a fluid case are attached to the test substrate 31. The test circuit 36 and the test circuit 37 are cooled by a cooling agent, such as a fluorine-based liquid, that fills the space between the test substrate 31 and the sealing section 38 and the space between the test substrate 31 and the sealing section 39.
The test circuit 36 and the connector 60 are electrically connected to each other by a first penetrating through-hole 100, substrate wiring 110, a second penetrating through-hole 102, and substrate wiring 112. When the substrate wiring in the insulating board 32 and the substrate wiring in the insulating board 34 are near each other, cross-talk can occur between the substrate wirings. Therefore, the substrate wiring 110 is formed within the insulating board 32.
However, when the substrate wiring 110 is formed in the insulating board 32, a stab is formed between the intersection of the penetrating through-hole 100 and the substrate wiring 110 and the intersection of the penetrating through-hole 100 and the pre-preg 33. When a stab is formed, the signal waveform is distorted by the reflection occurring at the end of the penetrating through-hole 100. Furthermore, the high-frequency component caused by the distortion is emitted to the outside of the test substrate 31 as noise.
When the frequency of the transmitted signal is 2 GHz or more, the problem described above is particularly pronounced. By using a surface via hole (SVH) and an internal via hole (IVH), cross-talk can be prevented and the occurrence of stab can be eliminated. However, using SVH and IVH increases the cost of the test substrate.
Furthermore, the test circuit 36 and the test circuit 37 desirably have many functions. As a result, it is expected that the number of pins of the test circuit 36 and the test circuit 37 will increase. When the number of pins increases, the problem described above becomes even more pronounced.